Don't (Kernel) Panic!
Seems I forgot my towel when I needed it most. Nothing a pan-galatic-gargle-blaster won't fix. Anyway, Kernel during the optimization of the install. Checked logs, it wasn't the update, just a random kernel panic. Strangely enough 10.3.6 was the current system. Wiped the drive, reinstalled a 10.3.5 build and updated without any trouble. Thought I would point it out and at least give everyone a chance to ponder what the question to 42 is. Obviously: "At what percent of optimization during a system update in OS-X does a Kernel Panic occur?" Heh, kismet that.